Furnace for fusing porcelain



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(NoModeL) I W. M. SHARP. FURNACE FOR FUSING PORCELAIN, &c.

No. 499,476. Patented June 13, 1893.

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UNITED STATES PATENT O F-ICE.

WVARREN MILTON SHARP, OF BINGHAMTON, NEW YORK.

FURNACE FOR FUSING PORCELAIN, 80c.

SPECIFICATION forming part of Letters Patent No. 499,476, dated June 13, 1893.

Application filedDeoemher 12, 1892. Serial No. 454,875. (No model.)

To all whom it may concern:

Be it known that I, WARREN MILTON SHARP, a subject of the Queen of Great Britain, and a resident of Binghamton, in the county of Broome and State of New York, have invented certain new and useful Improvements in Furnaces for Fusing Porcelain for Dental and other Purposes; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to 1 make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates to improvements in furnaces for fusing porcelain for dental and other purposes, and for melting metals of various descriptions, of that class in which a mixture of gas and air is employed as the heating medium.

The object of the invention is to provide a furnace of the above character, which shall possess superior advantages with respect to efficiency in operation.

The invention consists in the novel construction and combination of parts, hereinafter fully described and claimed.

In the accompanying drawings: Figure l is a side elevation of a furnace constructedin aocordance with my invention. Fig. 2 is a central longitudinal section of the same; and Fig. 3 is a perspective view of the rotatable springvalve, detached.

In the said drawings, the reference numeral 1 designates a bracket adapted to be hinged to a wall or other place or object, by which the furnace is supported. It is formed at its outer or free end with two curved boxes 2, provided with lugs3, through which passes a setscrew 4, by which the boxes may be clamped to avertical pipe 5. This pipe5 at its upper endis connected with the lower portion of the fur- The numeral 12 designates the upper portion or dome of the furnace made of fire-clay and provided with metallic strengthening bands 13, and is formed with an annular groove 14,- with which the flange 9 engages. This dome. is formed with a semicircular or approximately shaped opening 15, for the passage of a muffle 16, consisting of an ovenshaped vessel of fire-clay completely closed, except at one end, and is provided with a door 17 for closing said opening, and also-the opening in the dome. This muffle in crosssection corresponds in shape and size with the openingin the dome, so that when inserted in said opening,it completely closes the same.

At its lower end the pipe 5, which serves as a mixing chamberis provided with a gas-pipe l8, and an air-pipe 19, for supplying gas and air thereto. N ear its end it is also provided with a slot 20, which is opened and closed by a rotatable spring-valve 21, consisting of a spring-metal sleeve having a space or opening between its ends. The upper end of the pipe 5, Where the mixed gas and air is ignited, is provided with a wire-gauze plate 22, which prevents access of the flame to the burner.

The operation is as follows: The articles to be fused or baked are placed in the mufile which is inserted into the dome through the opening therein. The dome is then placed in position closing the open end of the muffle. The muffle is supported upon the radial partitions or wings 8. Gas and air are thus forced into the mixing pipe and ignited at the upper end thereof. By means of the slot or opening in the pipe 5, and the valve 21,air may also be admitted into said pipe, independent of the supply pipe.

From the above it will be seen that the articles in the muffle can be inspected at any time, by simply removing the door, without necessitating the removal of the muffle from the furnace, as the muffle fitting snugly in the opening prevents the escape of the products of combustion.

Another important advantage is gained, in that the muffle may be slowly inserted in the furnace, thus gradually heating the contents thereof, and obviating liability of their cracking, which is frequently the case when heated too rapidly. The muffle being completely closed against entrance of the products of combustion, there is no danger of the dentures or other objects being injured thereby.

Having thus described my invention, what I claim is- In a muffle furnace, the combination with the lower portion having a circular recess and radial Wings or partitions, a mixing pipe leading thereto, and the gas and air supply pipes leading to the mixing pipe, of the dome having an approximately semicircular opening,

the open-ended muffle corresponding in contour with and fitting closely in said opening, and the door closing said muffle and opening, substantially as described.

In testimony that I claim the foregoing as my own I have hereunto aifixed my'signature in the presence of two witnesses.

WARREN MILTON SHARP.

Witnesses:

A. B. SMITH, J r., JEROME DE WITT. 

